Textile fiber web former and electrical means for maintaining constant thickness thereof



Nov. 24, 1964 K. G. I YTTON ETAL. 3,158,291

TEXTILE FIBER WEB FORMER AND ELECTRICAL MEANS FOR MAINTAINING CONSTANT THICKNESSTHEREOF v 4 Sheets-Sheet l Filed Sept. 13, 1961 Nov. 24, 1964 K. G. LYTToN E'rAL 3,158,291

TEXTILE FIBER WEB FORMER AND ELECTRICAL MEANS FOR MAINTAINING CONSTANT THICKNESS THEREOF Filed Sept. 15, 1961 Y 4 Sheets-Sheet 2 Nov. 24, 1964 K. G. L YTToN ETAL 3,158,291

WEB FORMER AND ELECTRICAL MEANS FUR TEXTILE FIBER MAINTAINING CONSTANT THICKNESS THEREOF Filed Sept. 13, 1961 4 Sheets-Sheet 5 BY i ,W7 ATTORNEYS Nov. 24, 1964 K c; Y'r1'oN ETAL 3158,291

. 9 TEXTILE FIBER WEB FORMER AND ELECTRICAL MEANS FOR MAINTAINING CONSTANT THICKNESS THEREOF Filed Sept. 13, 1961 4 Sheets-Sheet 4 INVENTORS ZA/A/frv www vfc/. .S M55 ATTORNEYS United States Patent 3,158,291 TEXTILE BEBER WEB FRMER AND ELECTRECAL MEANS EUR MAILNTANING CGNSTANT THICK- NESS THERESE Kenneth G. Lytton and Cecil S. Wise, Gastonia, N.C., assignors to Fiber Conti-ois Corporation, Gastonia, N.C., a corporation of North Carolina Filed Sept. 13, 1961, Ser. No. 137,91@ 20 Claims. (Cl. 222-39) This invention relates to textiles and, more particularly, to improved equipment for feeding textile fibers in a moving stream or web and for maintaining said web of a substantially constant weight per increment of length desirably by maintaining the thickness and density of such web substantially uniform both transversely and in the direction of movement thereof. More pmticularly, this invention relates to improvements in the apparatus disclosed in the copending application of Kenneth G. Lytton, Serial No. 857,140, now Patent No. 2,995,783 of August l5, 1961. This application is a continuationdnpart of the application of Lytton et al., Serial No. 51,959, filed August 25, 1960, now abandoned. Although the invention will be described with particular reference to feeding textile bers into a carding machine, commonly termed a card, it will be realized that the invention will have applications other than card feeding, such as feeding picker hoppers, and other types of textile processing equipment.

Cards, as is well known in the art, form rovings or slivers, i.e., rope-like lengths of textile bers that are in a somewhat parallel though loose and fluffy condition. Thread and yarn are made from roving and sliver by drawing and spinning operations. In order to maintain yarn uniformity without excessive doubling operations, it is essential that roving or sliver be of substantially uniform composition and weight throughout its length. The formation of uniform roving or sliver isv dependent, to a great extent, on the maintenance of a uniform feed of fibers into a card.

In making sliver, fibers usually are fed into a card inthe form of allap made by a picker. Picker laps are, however, notoriously lacking in uniformity. As a consequence, conventional cards maintain sliver variation only within .030 inch, a tolerance considered excellent in the industry. Sliver variation is measured by a standard test, which involves both compression and pull-through of the sliver on a testing machine of a type well known in the art.

In making roving, cards usually are fed by so-called Weighing-feeds of the Bramwell type, which also include a push board for compacting and shaping succeeding batches of fibers that are dropped onto a card feeding apron. The feeding of cards by such weighing-feeds and push boards, however, usually results in roving having a greater variation, or lack of uniformity, than sliver made on cards with picker laps.

Accordingly, it is an object of this invention to provide an improved method and apparatus for feeding a textile card.

It is another object of this invention to provide a novel method and apparatus for feeding a textile card which will result in sliver variations of no more than .O inch.

It is another object of this invention to provide an imN proved method and apparatus for feeding textile fibers in a moving web of a substantially constant weight per increment of length.

It is another object of this invention to provide an improved and simplified method and apparatus for feeding textile bers in a moving web of substantially uniform thickness and density throughout, without resort to weighice ing the fibers, and which maintains the thickness and density of the web of greater uniformity than methods and apparatus which involve the weighing of the fibers.

Other objects and advantages of the invention will become apparent from the following description and accompanying drawings in which:

FIGURE 1 is a Isomewhat schematic and diagrammatic View of apparatus embodying this invention for feeding a textile card.

FIGURE 2 is an enlarged fragmentary horizontal sectional view taken substantially on line 2 2 of FIG- URE 1.

FIGURE 3 is an enlarged fragmentary sectional view taken substantially on line 3 3 of FIGURE 2.

FIGURE 4 is a fragmentary view corresponding to FIGURE 1 but illustrating an additional feature of the invention.

FIGURE 5 is an enlarged fragmentary sectional view taken ysubstantially on line 5 5 of FIGURE 4.

FIGURE 6 is an enlarged fragmentary sectional View taken substantially on line 6 6 of FIGURE 4.

FIGURE 7 is a fragmentary view of a portion of FIG- URE 4 but illustrating a further development of the inven tion.

FIGURE 8 is a fragmentary view corresponding to FIGURE 4 but illustrating a somewhat different development of the invention.

Referring now to FIGURE 1 of the drawings, there is shown a liber processing and feeding machine 11i of a type well known in the art. The machine 10 includes a housing having side and rear Walls l2 and 14 partly defining a hopper 16 provided with an opening 17 adjacent its top rear through which fibers are deposited, usually by hand. At the bottom of the hopper 16 is an endless conveyor which includes an apron 18 trained over front and rear rollers 20 and 22. The conveyor moves the fibers forwardly into engagement with an upwardly and forwardly extending spiked apron 24 trained over upper and lower rollers 26 and 28. The spiked apron 24 picks up the bers and moves them upwardly out of the hopper 16. Adjacent the top of the spiked apron 24 is a Sargent comb 3i) which oscillates in close proximity to the spiked apron to strip therefrom surplus fibers so that upwardly beyond the comb the aprong 24 carries a web or mat of fibers of generally uniform thickness. In front of the upper roller 26 of the apron is a rotating doffer 32 which strips the fibers from the apron 24 and allows them to fall downwardly, in opened condition, through ay generally rectangular discharge Opening 34 in an overhanging portion of the machine 10.

The machine is driven by a conventional electric motor 36 that may be secured to the housing front wall 38 and has a belt drive 40 to one end of the shaft of the doffer 32. The spiked apron 24 preferably is driven by a variable speed drive 42 between the shaft of the doffer 32 and the shaft of the upper spiked apron roller 26, while Ithe hopper bottom conveyor 18 is driven by a belt 44 trained over the shaft of the lower spiked apron roller 28 and the shaft of the front rollerf20. The variable speed drive 42 is not shown in detail because it may be of any suitable type, for example, that described in detail in the aforementioned Lytton aplower portion 54 of the rear Wall 52 of the chute 46 is movable between the side walls 48 toward and away from the front wall i) (but only in a range rearwardly of the upper portion of the rear wall 52) to vary the front-to-rear dimension, and consequently cross-sectional area, of the lower and operative section of the chute 46. Such movement can be effected, for example, by supporting the rear wall lower portion S4 on the ends of horizontal racks 56 mounted in slideways 58 fixed to the side walls 48 and engaged with pinions 69 mounted on a horizontal cross shaft 62, as shown more in detail in FIGURES 2 and 3. Obviously, rotation of the shaft 62 will move the chute rear wall lower portion 54 toward or away from the chute front wall 50.

At the bottom of the chute 46 is an endless conveyor having a horizontal apron 64 trained over front and rear rollers 66 and 63. The rear wall portion 54 of the chute 46 depends into close proximity to the apron 64, while the chute side walls 43 depend therebelow to form side walls for the conveyor, as well as side walls for the chute. Adjacent the front wall Sii of the chute 4o is a press roll 70 adapted to ride on fibers being carried forwardly out of the bottom of the chute on the apron 64. The press roll 7l? is maintained in position by end stub shafts received in vertical guideway notches 72 in front extensions of the side walls 48 of the chute 46. The front wall 50 of the chute 46 depends into close adjacency with the rear side of the press roll 70, so that the latter essentially forms the lower portion of the front wall of the chute.

It will be seen that when the upper reach of the apron 64 moves forwardly, it will feed fibers out of the chute 46 in a relatively thin flat web or stream. For some types of fibers, particularly some types of rather stiff, long, and resilient fibers employed to make carpet yarns, it is desirable to drive the press roll 70 at the same peripheral speed as the apron 64, as by reversed belts 71 trained over the press roll stub shafts and the shaft of the front apron roller 66. In some cases it may even be desirable to replace the driven press roll 7l) with a short forwardly and downwardly inclined endless conveyor (not shown) of the so-called nip type known in the art in order to better form the web of fibers on the apron 64.

In use of the apparatus to feed a card, for example, the front roller 66 of the web-feeding conveyor is positioned closely adjacent the feed rolls 74 of the card 76, only a portion of which is illustrated diagrammatically in FIGURE l. The card feed rolls 74 receive the web emerging from beneath the press vroll 70 and feed it to the conventional licker-in 78 of the card 76. The web-feeding conveyor is driven ata constant rate by or in synchronism with the card 76, such as by means of an appropriate drive train 80 (not shown in detail) between the card and the stub shaft of the front conveyor roller 66.

The weight per increment of length of the web being fed by the apron 64, and to some extent its thickness and density, depends upon the density of the fibers at the bottom of the chute 46. The density at the bottom of the chute depends both upon the height of the fibers in the chute and the degree of their openness. An increase in the height of bers in the chute will result in a greater weight of fibers pressing down on the apron 64, with a consequent increase in density of the fibers at the lower end of the chute. The converse obviously is true. On the other hand very open bers, such as waste sliver and roving which usually is reprocessed, will have less density at the lower end of the chute, for a given height of fibers therein, than will bers that are not as open. Consequently, in order` to maintain uniformity of weight per increment of length in the web being formed on the apron 64, the density of the bers at the lower end of the chute 46 should be maintained substantially constant.

In order to maintain the fibers in the lower position of the chute 46 at a substantially constant density, this invention makes use of electronically-controlled appa-V ratus for sensing the density of the column of bers and controlling the driving motor 36 of the feeder 1i) in a manner so that the density of the fibers in the lower portion of the chute is maintained substantially constant. The sensing mechanism makes use of the at.- tenuation which occurs in a beam of sonic or ultrasonic Wave energy on passage through a column of fibers. Thus, as illustrated in FIGURE 1, use is made of a sonic or ultrasonic signal beamed across the chute 46 from one side to the other and through the column of fibers therein. Variations in amplitude or intensity of such signal at the other side of the chute, because of the attenuation thereof by fibers in the chute, are used to control the operation of the feeder driving motor 3o. It readily will be seen that a sonic or ultrasonic signal beamed from one side of the chute to the other is not particularly affected by open fibers falling freeing, a1- most like snow flakes, through the beam. On the other hand, a column of fibers interposed in the beam will affect the intensity thereof, i.e., attenuate the beam so as to lower its amplitude at the receiving side of the Y chute, i.e., that side thereof opposite the source of the beam.

in one operative embodiment of the invention the beam was of sonic frequency and created by an electric trans ducer, in the form of a loud speaker mounted on a lower portion of a side Wall of the chute 4t?. Such transducer d?. may be, for example, a small cone-type tweeten and in actual practice, a Quant 3 speaker Model 3AG7 has been used with satisfactory results'. Preferably, fthe speaker 32 is secured to the outer end of a tubular mounting bracket 84 exteriorly surrounding an opening Se in a flat plate 37 covering a vertical slot S9 in the chute side wall 48. rihe opening 86 is aligned with the slot S9 so that the speaker S2 will beam sound across the chute toward the other side wall 48 without inteferd ing with the downward movement of fibers in the chute.

Also, it is preferable that the opening be covered byan acoustlcally transparent screen S8 or other perforated sheet material, again, Ato prevent interference with the downward movement of fibers in the chute by any of the edges of the opening Se. The plate il?, and consequently the speaker S2, preferably is secured and vertically atljustable along the slot 89, `as by edge clamps $1 retained in place by bolts and wing nuts 9o'.

The speaker 32 may be supplied with an electric signal Le., AC. current, of a desired audio frequency by means of an appropriately-powered electronic oscillator 93, ad# justed, for example, to generate a 468% cycle per secondA signal. rhe signal is passed from the oscillator 99 to an appropriately-powered tadjustable audio amplifier 92 and then is fed into the transducer $2 which converts the electric signal to audible sound of lthe same frequency. if the signal is audible, a single and relatively high fre` quency, such as 4600 cycles per second, is preferred, because, for reasons later explained, the entire system will not be subject to interference and malfunctioning because of extraneous noises of lower and mixed frequencies which are common in textile mills where heavy machinery is operating. Furthermore, high frequency sound is some# what directional in its characteristics so that it can more readily be transmitted in a bearrvlike form.

The sound beam produced lby the transducer 82 is directed toward another transducer 94 for creating an elec tric signal of an amplitude proportionate to that received from the beam. The second transducer 94 is in the fornil of a microphone 94 mounted on the opposite wall 43 of the chute 4o, preferably at the outer end of a tubular mounting bracket 9u surrounding an appropriately screened opening 98 a cover plate ll for a vertical slot lill `in the side wall 43. The plate 99 also is secured and vertically adjustable along the slot lill by edge clumps.

91, bolts 93, and wing nuts 95. A microphone that has been found to be suitable for tln's purpose is one manufactured by Shure Brothers, Inc., Model R7 crystal microphone. The electric signal from the microphone 94 is fed to Van appropriately-powered amplifier 1in), and thence through an electric filter network 1152 which passes only the frequency emitted by `the speaker @2, eg., 4600 cycles. -t will be seen that because the filter 192 passes only the frequency emitted by the speaker S2, the entire system is not susceptible to malfunctioning. because of extraneous noises. The signal, after passing through the filter 162, is fed -to an appropriately-powered electronic control relay rtl4 which has a normally-open switch (not shown) that controls m energizing circuit for a control relay 166 for the feeder motor 35. Such circuit, which includes the coil of relay 1136, may be supplied with power from any suitable source, such as two of three conductors 108 which supply three phase power to the motor through the normally-open contacts of the relay 196. Preferably a manually operable switch 11d is connected into the energizing circuit for the relay 1de. The arrangement is such that when the electric signal passing through the ter 1@ is of a predetermined amplitude, the electronic control relay 1194 is energized and closes its switch which, in turn energizes the motor control relay 1116 so that the feeder motor 36 runs to thereby cause the feeder 1t? to deliver fibersinto the chute 46. Conversely, when the signal fails below a predetermined amplitude, the relay 1.@4 is (le-energized vand thus shuts olf the feeder motor 36.

As stated heretofore, fibers falling in what may be termed a snowflake iashion 'through the sound beam ,emitted by the speaker S2, have substantially no attenuatinfr effect upon the intensity of #the beam at the microphone 94. On the other hand, when bers build up in .the chute 46 and form a column therein which intercepts the beam, the intensity thereof at the microphone is substantially diminished directly `proportionately -to the density of the column at the level of the beam. The amplifier 92 is adjusted so that when the density of the fiber column, at the level of the beam, reaches a predetermined value, the intensity of the signal received by the transducer' 94 falls below the predetermined intensity necessary to energize the relay lil-4. Consequently, the electronic control relay 164 is de-energized and interrupts the energizing circuit of the motor control relay 106 so that the feeder motor 34 wil cease operating the feeder 1d to deliver fibers into the chute Conversely, when the density decreases, because of withdrawal of fibers by the apron e4, to a value where the intensity of the beam at the transducer 94 re-energizes the relay 1134, the motor 36 recomniences to feedlibers into the chute to increase the density.

Although this system of control operates on an on and olf principle, in an actual installation the system has been operated to maintain the density of the column of fibers in the chute 46, at the level of the beam, substantially constant during operation of the system. It is apparent that it is desirable to adjust the feeding rate of the feeder 1t), as by adjusting the variable speed drive 42, so that it is only slightly greater than the rate of withdrawal of fibers from the chute 46 by the apron 64.' When so adjusted the feeder will have fewer off periods, and the density ofthe column of fibers in the chute, at the level of the beam, will be even more constant.

The density of the fibers in the chute 46, at the level of the beam, and thus the thickness and density of the web being formed and fed by the apron 64, preferably is controlled by adjusting the output of the audio amplifier 92, although it would be possible to achieve similar results .by adjusting the output of the amplifier 109. A greater volume of the sound `beam emitted by the speaker 82 penetrates .the column of fibers more readily than will a beam of lesser volume. Hence, the greater the volume or intensity of the sound beam, the greater will be the 6 density of column of bers in the chute 46 at the level of the beam, and vice-versa.

The weight per increment of length of the web also can be controlled by adjusting the dimension of the column in the direction of web movement by moving the lower portion 54 of the rear wall 52 of the chute 46. An increased size in this dimension of the column will result in a greater weight in the column of fibers resting on the apron 64 and consequently an increased weight per increment of length of the web, and vice-versa.

The apparatus also has been operated most successfully with a beam of ultrasonic energy having a frequency of the order a 30,000 to 40,000 cycles per second. In this case the loud speaker and microphone transducers 82 and 94 were replaced with transducers of piezo-electric quartz crystal and the electrical components of the oscillator 911, ampliers 92 and 100, filter 102, and relay 104 modified accordingly. The use of such a high frequency beam not only avoids even further the possibility of interference with the sensing system by extraneous frequencies, but also eliminates the annoyance attendant a beam of audible frequency.

At both frequencies, it is desirable for the beam to traverse a lower portion of the column of fibers so as to minimize attenuation variations occasioned by different portions of the column being made up of fibers of different degrees of openness.

It is obvious that the foregoing web-forming apparatus will not function properly if the hopper 16 of the feeder 10 is not kept supplied with fibers. When the density of the column of fibers at the level of the beam falls to a predetermined level, the above-described electronic control system automatically starts the feeder 10 to feed further fibers into the chute. In the event, however, that the feeder 10 has run out of fibers or the quantity Vof fibers in its hopper 16 is so small that its actual feed rate is diminished, the density at the level of the beam simply will continue to decrease, instead of being built up to the predetermined value which will automatically shut olf the further feeding of fibers into the ,chute 46. The result obviously will be a web of diminishing weight per `increment of length, a most undesirable occurrence. Accordingly, this invention also includes means for signalling an operator when the feeder commences to run out of fibers to an extent that when it is automatically started by a decrease in density of the column of fibers in the chute the actual feeding rate is so diminished that the density of such column fails'to build .back up again.

Referring again to FIGURE l of the drawings, it will be seen that the electric signal developed by the transducer 94, after passage through the filter 102, also is fed to a second electronic control relay 112 of adjustable sensitivity. The relay 112, in turn, has a normally-open switch (not shown) which controls an energizing circuit for an appropriate signal perceptible by an operator, and which may be either visual, in the form of a lamp 114, as shown, or audible, in the form of a bell, horn, or the like (not shown) or a combination of the two. The sensitivity of the relay 112 is adjusted so that normally its switch will not be closed and the signal 114 will not be operated until the electric signal passing to the relay 112 from ythe filter 102 reaches a predetermined amplitude slightly greater than that necessary -to energize the relay 164. In other words, the sensitivity of the relay 112 is adjusted so that the alarm 114 will not be energized until the density of the column of fibers in the chute at the level of the beam falls to a predetermined value below that at which the electronic control relay 104 0perates the motor control relay 106 to start the feeder 10. Thus, when the density of the column of fibers falls below a predetermined value, the operator of the apparatus is notified that fibers are not being fed properly into the chute 46 in order to maintain the density of the column of fibers therein substantially constant at the level of the beam.

The relay 112 can be used not only to signal an operator that the feeder requires fibers, but also to automatically prevent the density of the column of fibers in the chute from decreasing appreciably below that at which the feeder recommences to feed. At the same time the relay 112 can be used to automatically shut off subsequent iiber processing machinery being fed by the apparatus until the density of fibers in the chute has increased to the predetermined value which will create the desired weight per increment of length in the web of fibers being fed.

Thus, for example, referring to FIGURE 4 of the drawings, the relay 112 may be employed to actuate means for increasing the set feed rate of the feeder when the density of the column of fibers in the chute at the level of the beam 46 falls a predetermined value below that at which the electronic control relay 104 operates the motor control relay 106 -to start the feeder 10. At the same time the relay 112 may also be employed to stop any subsequent fiber processing machinery, such as the card 76, being fed by the apron 64 until the density of the column of fibers, at the level of the beam, builds up suiiiciently to insure the desired weight per increment of length of the web.

The feed rate increasing mechanism may consist of a variable speed drive 42 like that disclosed in the aforementioned copending application of Lytton, Serial No. 857.140. This variable speed drive 42, which is shown in detail in FlGURES 4 to 6, includes a variable eifective diameter sheave 116 fixed to the end of the shaft 113 of the dofer 32. The sheave 116, as is well-known in the art, includes two halves or parts 120 having inclined opposed edges 122 to form the side walls of a circumferential groove for receiving a V-belt 124, as shown in FIG- URE 6. The two parts 120 of the sheave 116 are constantly urged toward each other by a spring 126 so as to increase the effective diameter of the sheave as respects the belt 124. lt will be seen, however, that when a sufiicient pulling force is exerted on the belt 124, it will spread the parts 120 to reduce the effective diameter of the sheave 116. When the eective diameter of the sheave 116 is so reduced the belt 124 will drive another part at a lower speed than when the effective diameter of the sheave is increased.

Rotatably mounted on the end of the shaft of the upper roller 26 for the spiked apron 24 is a gear housing 128 en'- closing a gear 130 fixed on'the shaft, as shown in FIG- URE 5. A pinion 132, meshing with the gear 130, is

journalled in the side walls of the housing 128 and hasy a projecting stub shaft carrying a sheave 134 over which the belt 124 is trained to drive the spiked apron 214. A single-acting reciprocating fluid motor 136, adapted to retract its piston rod 133 on the supply of fluid pressure to its cylinder throu gh a hose 140 from a suitable source, has the closed end of its cylinder connected by a link 142. to the gear housing 1218 at a location adjacent the pinion gear 132. The end of the piston rod 13S of the motor 136 is pivotally connected to `a lever 144 which has one end thereof pivotally connected, at 14", to the side 12 of the feeder housing for manual limited angular adjustment. The other vend of the lever 144 carries a springpressed retractible pin 14S adapted to project, when aligned therewith, into any one of an arcuately-arranged series of recesses or holes 150 in a quadrant-plate 152 iixed to the side wall 12 of the feeder housing.

From the foregoing construction it will be seen that when fluid pressure is supplied to the motor 136 and the pin 143 is in a hole 150, the rod 13S will retract and swing the gear housing 12S in a direction to increase the distance between the sheaves 116 and 134, thus spreading the parts 120 of the sheave 116 and reducing the driven speed of the sheave 134. When the motor is exhausted the piston rod 13S extends, because of the extending force exerted thereon by the belt 124, and thus allows the parts 120 of the sheave 116 to move toward each other and increase the driven speed of the sheave 134. The speed of the sheave 134, and consequently the spiked apron 24 and the conveyor 13, can also be adjusted, in either the pressurized or exhausted condition of the motor 136, by manually changing the angular position of the lever 144 and relocking it in place by engaging the pin 148 in a selected one of `the holes 150.

The supply and exhaust of pressure fluid to and from the motor 136 is controlled by a two-way solenoid valve 154 connected into a supply conduit leading to the hose The valve 154 is arranged so that when it is de-energized, pressure iiuid is supplied to the motor 136 thus causing the feeder 10 to be driven at slow speed, and when the valve 154 is energized, the supply of fluid pressure is shut off and the motor 136 exhausted, thus causing the feeder to be driven at high speed. The energizing coil of the solenoid valve 154 is controlled by the normally-open switch of the relay 112. Accordingly, when the relay 112 energiles the solenoid valve 154, via the conductors 10S, 156, 153, and 160, the feeder 10 will be driven at high speed and will thus tend to build the density of fibers in the chute 46 baci` up to the desired predetermined value. Such increased feed rate will ccntinue for an appreciable period of time, i.e., until the density at the level of the beam increases to the value at which the relay 112 is de-energized and its switch closed. The time period required for such density increase usually will result in building the density, at the level of the beam, to a value somewhat above that at which the relay 104 becomes de-energized.

It is evident that instead of using an on and off system of control edected by the relays 104 and 106, a

modulating system of controlcould be employed by having the motor 36 run constantly and varying the feed rate of the feeder 10 by the speed changer 42. Thus, the feed rate can be varied by using the relay 104, instead of the relay 112, to control the speed-change controlling valve 154. 1n such an event, when the density at the level of the beam drops to a predetermined value the relay 104 is energized `and closes its switch in an energizing circuit for the valve 154 to thus increase the set feed rate of the feeder 10. Such increase in feed rate will build the density at the level of the beam up to a point Where the relay 104 is (le-energized and allows the feed rate of the feeder 10 to drop back to a set low rate. Such low rate obviously should be slightly less than that Iequired to maintain the density, at the level of the beam, at the desired value.

Since it obviously is undesirable for the apparatus to create and feed a ber web of less than the desired weight per increment of length, i.e., less than that being created at the time that the relay 112 is energized to either signal an attendant or speed up the feeding of bers into the chute 46, or both, the relay 112 may also be used to stop movement of the web-forming apron 64 untilrsuch time as the density of the column at the level of the beam has built up to that necessary to enable the apron 64 to create the desired web weight. Thus, for example, in those instances where the web-forming apron 64 is driven by or in synchronism with a subsequent fiber processing vmachine 162 being fed by the apron 64, means operable by the relay 112 may be provided for disconnecting the drive for the apron 64. Such means, for example and as shown in FGURE 4, may take the form of an electrically-controlled clutch 164 interposed in an appropriate drive 166 between the subsequent fiber processing machine 162 and the front roller 66 of the apron 64. The clutch 164 is arranged so that it is engaged when de-energized, and disengaged when energized. The operating coil of the clutch 164 is connected, by the conductors 168, in parallel with the solenoid valve 154 so as to be operated simultaneously with the latter.

From the foregoing construction, it will be seen that when the density of fibers in the chute 46' at the level of the beam drops below a predetermined value, not only will the feeder be operated at an increased speed, to thus build up the density to that necessary to cause the web being formed on the apron 64 to have a desired weight per increment of length, but also formation and feeding of such web will be discontinued until such density has been reattained.

In lieu of disconnecting the drive 166 for the apron 64, the relay 112 may be alternatively employed to stop the operation of the subsequent fiber processing machine 162. Thus, for example, as shown in FIGURE 7, the machine 162 may be driven by a conventional electric motor 170 which is supplied with three-phase power by the conductors 172 and controlled by an electric relay 174 having three sets of normally-closed contacts. The energizing coil of the relay 174 is connected in parallel with the solenoid valve 154 via the conductors 168. Consequently, whenever the density of fibers in the chute 46 at the level of the beam drops below the predetermined density at which the relay 112 is energized, the subse quent fiber processing machine 162, as well as the fiber feeding apron 64, is stopped.

Referring now to FIGURE 8 of the drawings, there is shown an alternative method for increasing the rate of feed of the feeder 10. In this embodiment of the invention, the feeder 10 is provided with a press plate 176, of a type known in the art. The plate 176 is secured by arms 178 to, and depends from, a transverse rock shaft 18) journalled in the side walls 12 of the feeder housing. The shaft 180 is located slightly above that on which the comb 30 is secured and the arms 178 are angularly secured to the plate 176 in a manner to avoid interference veu'th the comb shaft. The plate 176 is urged toward the spiked apron 24 by means later described in greater detail. As is known in the art, the greater the force with which the press plate 176 is urged toward the spiked apron 24, the greater will be the actual rate of discharge of the feeder 10, and vice-versa.

Fixed to the rock shaft 180 is a sprocket 182 having one end of a roller chain 184 secured thereto and wrapped thereabout in a direction so that a pull on the chain serves to urge the press plate 176 toward the spiked apron 24. The chain 184 may be trained over an idler sprocket 186, journalled on a side wall 12 of the feeder housing, and is connected to one end of a coil tension spring 188, the other end of which is connected to the free end of the piston rod 19d of a fluid pressure motor 192 having its cylinder fixed to the corresponding side wall 12 of the feeder housing. Fluid pressure may be supplied to or exhausted from the motor 192 via an appropriate conduit or hose 194 having a suitable solenoid control valve 196 interposed therein.

The arrangement is such that when the coil of the valve 196 is energized, Huid under pressure is supplied to the motor 192 and operates to retract the piston rod 19t). When the coil of the'valve 196 is de-energized, the motor 192 is exhausted so that the rod 190 may extend. Obviously, when the coil of the valve 196 is energized, the chain 184 is pulled by the motor 192 in a direction to increase the spring force urging the press plate 176 toward the spiked apron 24 to thus increase the actual feed .rate of the feeder 10. Conversely, when the coil of the valve 196 is de-energized, the feed rate of the feeder 10 is decreased. The coil of the valve 196 is controlled by the normally-open switch of the relay 112, so that when the latter is energized the feed rate of t-he feeder 10 is increased, and vice-versa.

lt thus will be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the foregoing specific embodiments have been shown and described only for the purpose of illustrating the principles of this invention and are subject to extensive change without departure from such principles. Therefore, the invention includes all 10 modifications encompassed within the spirit and scope of the following claims.

We claim:

l. Fiber feeding apparatus comprising: a tubular chute generally rectangular in cross-section for forming and holding a column of fibers; means for withdrawing fibers from the lower end of said chute at a uniform rate in the form of an endless substantially uniform web; means for feeding fibers in an open condition into said chute; means for creating and directing from one side to an opposite side of said chute, through and at a predetermined level in a coiumn of fibers therein, a beam of wave energy of constant intensity and of a frequency such that the attenuation of said beam at said chute opposite side is proportional to the densi-ty, throughout a substantial range, of that portion of the column of fibers which intercepts said beam; and means responsive to variations in the intensity of said beam at said chute opposite side for modifying the rate of feed of said fiber feeding means to maintain a substantially constant density at said level to thereby maintain a substantially constant weight per increment of length of said web.

2. The structure defined in claim l in which the withdrawing means includes endless conveyor means immediately beneath the chute.

3. The structure defined in claim l in which the withdrawing and web-forming means includes an endless conveyor covering the lower end of the chute and a nip element opposed to said conveyor and rotating at the same peripheral speed and in the same direction thereas adjacent the lower edge of a side wall of said chute.

4. The structure defined in claim l in which the fiber feeding means comprises a feeder having a hopper and a spiked apron.

5. The structure defined in claim 1 in which the beam of wave energy is sonic.

y6. The structure defined in claim l in which the beam of wave energy is ultrasonic.

7. The structure defined in claim 1 in which the fiber feeding means includes a feeder having a hopper and a spiked apron, and the withdrawing and web-forming means includes an endless conveyor covering the lower end of the chute.

S. Fiber feeding apparatus comprising: a tubular chute generally rectangular in cross-section for forming and holding a column of fibers; means for withdrawing fibers from the lower end of said chute at a uniform rate in the form of an endless substantially uniform web; means for feeding fibers in an open condition into said chute; a pair of transducers on opposite sides of said chu-te, one transducer for emitting and directing a beam of wave energy across the interior of said chute through a column of fibers therein toward the other transducer, the frequency of said beam being such that its attenuation at said other transducer is proportional to the density, throughout a substantial range, of that portion of the column of fibers which intercepts said beam, and said other transducer for developing an electric signal in response to said beam proportional to the attenuation thereof; means for supplying said one transducer with electric power to' develop a beam of constant intensity; and means responsive to variations in the electric signal developed by said other transducer for controlling said fiber feeding means, whereby variation in the density of the column of fibers at the level of said beam affects reception of the beam by said other transducer and thereby controls the fiber feeding means to feed fibers into the chute in a manner to maintain a substantially constant density at said level to thereby maintain a substantially constant weight per increment of length in said web.

9. The structure defined in claim 8 in which the power supplying means for the one transducer is adjustable for varying the intensity of the wave energy emitted by said one transducer, whereby to adjust the density of the l l column of fibers in the chute at the level of the beam, and thus the weight per length increment of the web.

10. The structure dened in claim 8 in which 4the means responsive to the electric signal renders the fiber feeding means operative or inoperative, depending upon a predetermined intensity of said signal, and including alarm means and means responsive to a greater intensity of said signal for operating said alarm means when the density of the column of fibers at the level of the beam decreases a predetermined value below that at which said fiber feeding means is rendered operative.

11. The structure defined in claim 8 in which the power supplying means for the one transducer includes an electronic oscillator for generating an electric signal substantially of only a single frequency and the means responsive to the electric signal generated by the other transducer includes an electric filter for passing therethrough substantially only the frequency generated by said oscillator.

l2. The structure defined in claim 8 in which the means responsive to the electric signal includes an electronic relay.

13. The structure defined in claim 8 in which the fiber feeding means is adjustable to feed fibers at a slower or faster rate and wherein the means responsive to the electric signal automatically adjusts said feeding means to feed fibers at a slower or a faster rate.

14. Fiber feeding apparatus comprising: a tubular chute generally rectangular in cross-section for forming and holding a column of fibers; means for withdrawing fibers from the lower end of said chute at a uniform rate in the form of an endless substantially uniform web; means for feeding fibers in an open condition into said chute including means for varying the feed rate of said fiber feeding means between lower and higher rates; a paiL3f transducers on opposite sides of said chute and adjacent the upper end thereof, one transducer for emitting and directing a beam of wave energy across the interior of said chute toward the other transducer, the frequency of said beam being such that its attenuation at said other transducer is proportional to the density, throughout a substantial range, of that portion of the column of fibers which intercepts said beam, and said other transducer for developing an electric signal in response to said beam proportional to the attenuation thereof; means for supplying said one transducer with electric power to developl a beam of constant intensity; first means responsive to the electric signal developed by said other transducer for rendering said fiber feeding means operative or inoperative, depending on the intensity of the beam received from said one transducer, whereby variation in the density of the column of fibers at the level of the beam affects reception of the beam by said other transducer and thereby controls the fiber feeding means to feed fibers into the chute in a manner to maintain in said chute a column of fibers of approximately constant density at said level to thereby maintain 'a constant weight per length increment of said web; and second means responsive to a greater intensity of the electric signal, than that to which said first means is responsive, for operating said feed rate varying means, whereby when the density of the column of bers at the level of the beam decreases a predetermined value below that at which said fiber feeding means is rendered operative, the feed rate of said liber feeding means is changed from a lower to a higher rate.

15. The structure defined in claim 14 in which the means for varying the feed rate includes a variable speed drive for the fiber feeding means.

16. rThe structure defined in claim 14 in which the fiber feeding means includes an upwardly inclined spiked apron and the means for varying the feed rate includes a pressure plate mounted for movement toward and away from said spiked apron adjacent the upper end thereof.

17. The structure defined in claim 14 including control means for the withdrawing means and wherein the second responsive means operates said control means to stop said withdrawing means when the density of the column of fibers at the level decreases a predetermined value be low that at which the fiber feeding means is rendered operative.

18. rl`he structure defined in claim 14 including fiber processing apparatus fed by the withdrawing means and control means for both said processing apparatus and said withdrawing means, and wherein the second responsive means operates said control means to stop said processing apparatus and said withdrawing means when the density of the column of fibers decreases a predetermined value below that at which the fiber feeding means is rendered operative. Y Y

19. Fiber feeding apparatus comprising: a tubular chute generally rectangular in cross-section for forming and holding acolumn of fibers; means for withdrawing fibers from the lower end of said chute at a uniform rate in the form of an endless substantially uniform web; means for feeding fibers in an open condition into said chute; a pair of transducers on opposite sides of said chute, one transducer for emitting and directing a beam of wave energy across the interior of said chute through the column of fibers therein toward the other transducer, the frequency of said beam being such that its attenuation at said other transducer is proportional to the density,

throughout a substantial range, of that portion of the column of fibers which intercepts said beam, and said other transducer for developing an electric signal in response to said beam proportional to the attenuation thereof; means for supplying said one transducer with electric power to develop a beam of constant intensity; first means responsive to the electric signal developed by said other transducer for rendering said fiber feedingl means operative or inoperative, 1spending on the intensity of the beam received from said one transducer, whereby variation in the density of the column of fibers at the level of the beam affects reception of the beam by said other trans` ducer and thereby controls the liber feeding means to feed fibers into the chute ina manner to maintain approximately constant density at the level of the beam to thereby maintain a constant weight per increment of length in said web; control means for said withdrawing means; and second means responsive to a greater intensity of the electric signal than that to which said first means is responsive for operating said control means to stop said withdrawing means when the density of the column of fibers at the level of the beam decreases a predetermined value below that at which said fiber feeding means is rendered operative.

20. The structure definedinclaim 19 including ber processing apparatus fed by the withdrawing means and wherein the control means also controls said processing apparatus in the same manner as the control means con-V trols the said withdrawing means.

yReferences Cited in the file of this patent UNITED STATES PATENTS 2,523,363 Gehman Sept. 26, 1950 2,618,395 De Brabander Nov. 18, 1952 2,737,997 Himmelheber et al Mar. l3, 1956 2,759,225 Hunter et al Aug. 2l, 1956 2,983,325 Moody May 9, 1961 

1. FIBER FEEDING APPARATUS COMPRISING: A TUBULAR CHUTE GENERALLY RECTANGULAR IN CROSS-SECTION FOR FORMING AND HOLDING A COLUMN OF FIBERS; MEANS FOR WITHDRAWING FIBERS FROM THE LOWER END OF SAID CHUTE AT A UNIFORM RATE IN THE FORM OF AN ENDLESS SUBSTANTIALLY UNIFORM WEB; MEANS FOR FEEDING FIBERS IN AN OPEN CONDITION INTO SAID CHUTE; MEANS FOR CREATING AND DIRECTING FROM ONE SIDE TO AN OPPOSITE SIDE OF SAID CHUTE, THROUGH AND AT A PREDETERMINED LEVEL IN A COLUMN OF FIBERS THEREIN, A BEAM OF WAVE ENERGY OF CONSTANT INTENSITY AND OF A FREQUENCY SUCH THAT THE ATTENUATION OF SAID BEAM AT SAID CHUTE OPPOSITE SIDE IS PROPORTIONAL TO THE DENSITY, THROUGHOUT A SUBSTANTIAL RANGE, OF THAT PORTION OF THE COLUMN OF FIBERS WHICH INTERCEPTS SAID BEAM; AND MEANS RESPONSIVE TO VARIATIONS IN THE INTENSITY OF SAID BEAM AT SAID CHUTE OPPOSITE SIDE FOR MODIFYING THE RATE OF FEED OF SAID FIBER FEEDING MEANS TO MAINTAIN A SUBSTANTIALLY CONSTANT DENSITY AT SAID LEVEL TO THEREBY MAINTAIN A SUBSTANTIALLY CONSTANT WEIGHT PER INCREMENT OF LENGTH OF SAID WEB. 